package com.example.base.http;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Locale;
import java.util.Map;

/**
 * The header of an entity (see RFC 2045).
 */
class MinimalFieldHeader implements Iterable<MinimalField> {

	private final List<MinimalField> fields;
	private final Map<String, List<MinimalField>> fieldMap;

	public MinimalFieldHeader() {
		super();
		this.fields = new LinkedList<MinimalField>();
		this.fieldMap = new HashMap<String, List<MinimalField>>();
	}

	public void addField(final MinimalField field) {
		if (field == null) {
			return;
		}
		String key = field.getName().toLowerCase(Locale.US);
		List<MinimalField> values = this.fieldMap.get(key);
		if (values == null) {
			values = new LinkedList<MinimalField>();
			this.fieldMap.put(key, values);
		}
		values.add(field);
		this.fields.add(field);
	}

	public List<MinimalField> getFields() {
		return new ArrayList<MinimalField>(this.fields);
	}

	public MinimalField getField(final String name) {
		if (name == null) {
			return null;
		}
		String key = name.toLowerCase(Locale.US);
		List<MinimalField> list = this.fieldMap.get(key);
		if (list != null && !list.isEmpty()) {
			return list.get(0);
		}
		return null;
	}

	public List<MinimalField> getFields(final String name) {
		if (name == null) {
			return null;
		}
		String key = name.toLowerCase(Locale.US);
		List<MinimalField> list = this.fieldMap.get(key);
		if (list == null || list.isEmpty()) {
			return Collections.emptyList();
		} else {
			return new ArrayList<MinimalField>(list);
		}
	}

	public int removeFields(final String name) {
		if (name == null) {
			return 0;
		}
		String key = name.toLowerCase(Locale.US);
		List<MinimalField> removed = fieldMap.remove(key);
		if (removed == null || removed.isEmpty()) {
			return 0;
		}
		this.fields.removeAll(removed);
		return removed.size();
	}

	public void setField(final MinimalField field) {
		if (field == null) {
			return;
		}
		String key = field.getName().toLowerCase(Locale.US);
		List<MinimalField> list = fieldMap.get(key);
		if (list == null || list.isEmpty()) {
			addField(field);
			return;
		}
		list.clear();
		list.add(field);
		int firstOccurrence = -1;
		int index = 0;
		for (Iterator<MinimalField> it = this.fields.iterator(); it.hasNext(); index++) {
			MinimalField f = it.next();
			if (f.getName().equalsIgnoreCase(field.getName())) {
				it.remove();
				if (firstOccurrence == -1) {
					firstOccurrence = index;
				}
			}
		}
		this.fields.add(firstOccurrence, field);
	}

	public Iterator<MinimalField> iterator() {
		return Collections.unmodifiableList(fields).iterator();
	}

	@Override
	public String toString() {
		return this.fields.toString();
	}

}
